Hormone-dependent neoplasms of the canine perianal gland.

The epidemiological features of 472 dogs with microscopically confirmed neoplasms of the perianal gland are described. These general characteristics suggest etiological factors similar to those responsible for hormone-related neoplasms occurring in human beings. Perianal gland tumors appear to be androgen dependent. Male dogs show a 5.6-fold-increased risk compared with females; endogenous estrogens offer protection and the use of estrogenic hormones is conventional therapy for the benign lesion. Both sexes of the cocker spaniel breed show excessively high risk, suggesting that this dog family may be a model for genetic studies that could be relevant to familial aggregations of hormone-related tumors in men and women. Adrenocortical hormones may play a role in the development of the tumor in female dogs. Research into alterations of the biochemical pathways of steroidogenesis in affected female dogs may provide clues to similar conditions in humans.